Former Senate staffer Jessica Rosenworcel has been described as shy, but the recently confirmed Federal Communications Commission member sounded the alarm after superstorm Sandy left huge swaths of the East Coast without cellphone coverage.

“It is time for an honest conversation about network reliability in the wireless and digital age,” she said in a pivotal Nov. 13 speech. “It is time to ask hard questions about backup power, and how to make our networks more dependable when we need them most.”

The next week, Sen. Charles E. Schumer, D-N.Y., cited Rosenworcel’s speech in a letter he wrote to the FCC urging it to develop a plan for improved coordination and reduced outages during future disasters. FCC Chairman Julius Genachowski responded swiftly with plans to hold field hearings on the matter. House Democrats requested congressional hearings as well.

Rosenworcel revived a debate about what authority Congress has granted regulators over wireless companies. The issue first played out following Hurricane Katrina, when the FCC tried but failed to mandate backup power generators for cellphone towers.

Although Congress has clearly provided the FCC with authority over traditional landline phones, the rules are murkier surrounding wireless. As the commission mulls taking action in the aftermath of Sandy, lawmakers are facing pressure to clarify what ability the agency actually has to do so.

“Congress can make sure that the FCC’s authority to enforce standards is clear and unambiguous,” Harold Feld, senior vice president of consumer advocacy group Public Knowledge, said in an interview. “That authority has been repeatedly challenged by network operators.”

After 25 percent of cell towers became inoperable in the areas hit by Sandy in late October, wireless companies worked with the FCC and disaster agencies on a voluntary basis to restore service. Rivals AT&T and T-Mobile even agreed to carry each other’s signals, but other companies notably did not.

If the FCC had greater authority, it could demand that wireless companies develop emergency plans, coordinate during disasters and be held accountable afterward for mistakes. But the agency has faced resistance when it tried to assert such control.

Wireless companies and the industry association CTIA sued over the backup power rule the FCC adopted in 2007 after Katrina, questioning the agency’s authority to issue such a mandate on carriers. Before a court could rule, the Office of Management and Budget objected that the FCC had failed to incorporate public comments in the regulation, and the commission retreated.

Feld said the tussle demonstrated how telecommunications laws are out of sync with the behavior of consumers, who expect their handheld devices to be as reliable as landlines, which are subject to regulations ensuring they work in emergencies. The problem is only becoming more acute, he noted, as more people depend on wireless and broadband technology: About 33 percent of American households now rely solely on cellphones.

Schumer contends that the FCC should work closely with industry this time around to avoid the sort of push-back it faced after Katrina.

“If we need legislation, we’ll do it,” Schumer said in an interview. “Now we’re having everyone work together, and we expect a proposal in about six months.”

Rep. Anna G. Eshoo, D-Calif., welcomed the upcoming FCC field hearings but said through a spokesman that Congress “should conduct its own examination.” She and other Energy and Commerce Democrats on Nov. 19 called for a hearing by the panel about the outages.

Rosenworcel, who served as communications counsel for the Senate Commerce, Science and Transportation Committee before being sworn in at the FCC in May, said she is open to congressional review of the issue.

“We should start looking at our statute to make sure we can serve the public interest,” she said in an interview.

But Rosenworcel also urged caution about pursuing regulation, saying the agency should work with carriers to determine what is needed. In addition to addressing “hard questions about backup power,” she said officials could help wireless companies access fuel for generators during supply shortages and better coordinate with state and local authorities during emergencies.

“I don’t see this necessarily as an issue of regulation or legislation or changing rules or changing laws,” she said. “I think the first thing we need to do is figure out what’s happened.”

Wireless companies are likely to agree with the commissioner on that point. Since the storm, CTIA has praised carriers for restoring networks quickly, given the devastation that the group’s vice president, Christopher Guttman-McCabe, has described as reaching “near Biblical proportions.”

Guttman-McCabe said part of what worked was the flexibility wireless companies had to react — absent regulations or rules that would have controlled their response. He noted that an eight-hour backup power rule would not have been a panacea during the East Coast storm, when power was out in some areas for multiple days.

“There’s no greater incentive that a policymaker can give to a carrier to keep up its network than its own incentive to make sure that its customers have access to that network,” he said.